Lamp mount



' H. H. CHUN Dec. 13, 1949 LAMP MOUNT Filed March 30, 1948 INVENTOR.Herbert H. Chan ATTORIIEY Patented Dec. 13, 1949 LAMP MOUNT Herbert H.Chun, Marblehead, Mass., assignor to Sylvania Electric Products Inc.,Salem, Mass., a corporation of Massachusetts Application March 30, 1948,Serial No. 17,872

1 Claim.

This invention relates to electric gaseous discharge devices and moreparticularly to elongated linear fluorescent lamps of the cold cathodetype.

An object of this invention is to provide an improved electrode mounttherefor.

Another object is to provide a reinforced stem therefor.

Further objects, advantages, and features will be apparent from thefollowing description when read in conjunction with the accompanyingdrawing in which:

Figure 1 is a side elevational view of a fluorescent lamp with one endthereof in section.

Figure 2 is an enlarged detail of a lamp mount showing one embodiment ofmy invention.

Figure 3 is an enlarged detail of a lamp stem showing another embodimentof my invention.

One of the many applications of elongated linear fluorescent lightsources is in the field of public transportation, such as subway andstreet cars for example. In this field, cold cathode fluorescent lamps,'72 and even 96 inches in length, have been employed. In installationsof this type the lamps are subjected to considerable shock andvibration. One of the deleterious effects of shock and vibration ischipping of the glass stem press. This chipping usually occurs when thelamp is subjected to a sudden and sharp shock which sets up a forcewhich displaces the electrode from its normal position. Displacement ofthe electrode stresses the electrode-supporting wires and sets up astrain in the stem press in which a portion of these wires is sealed.Sometimes this strain is quite severe and results in chipping of piecesof glass from the stem press. Vibration of the lamp then causes thesefree glass chips to move about within the lamp and, in so doing, scratchthe coating of fluorescent material with which the inner wall of thelamp envelope is provided. The stem reinforcement of my inventionminimizes the possibility of stem press chipping and fluorescent coatingdefacement.

In Figure 1, the fluorescent lamp I comprises an elongated tubular glassenvelope 2, the inner wall of which is provided with a coating 3 offluorescent material, the ends of which are provided with electrodes 4,a more detailed view of which may be had from a study of Figure 2, basesII, and base pins l2.

Figure 2 shows a lamp mount 5, one of which is :sealed in each end ofthe lamp envelope. The mount 5 comprises a glass flare 6, a stem press 1formed integral therewith, an exhaust tubulation terminating at one endin an aperture I4 through which the lamp may be evacuated and providedwith a filling of an inert gas or gases and a small quantity of mercury,and an electrode 4 mounted on lead wires 8 which are sealed in andextend through the stem press I. The stem reinforcing means shown inFigure 2 consists of a wire member 9 fixedly connected to and woundaround the lead wires 8 between the top of the stem press 1 and thelower end of the electrode 4. Preferably, the wire member 9 is welded toeach of the lead wires 8 and the ends of member 9 are welded to eachother.

Another embodiment or form of stem reinforcing means is shown in Figure3. It consists of a metal plate [0, provided with holes therein, throughwhich lead wires 8 extend. The metal plate is fixedly connected to thelead wires, preferably by welding it thereto.

Although I have shown three lead wires extending from the flare cavityl5, only one, of course, is necessary, and it is connected to the basepin I2 in the base II. I have found it convenient during a portion ofthe manufacturing operation to use three full-length lead wires and thensever two of them within the flare cavity. Since only one lead wire isnecessary to establish the necessary electrical connection, one may,without departing from the spirit of my invention, employ but one leadwire, and use two electrode-supporting wires or spuds which would beimbedded in the stem press.

When a fluorescent lamp, which has been provided with a stemreinforcement in accordance with the principles of my invention, issubjected to vibration or a shock which displaces the electrode 4 andstresses the lead wires 8, the resulting strain occurs primarily in thestem reinforcing member, the wire member 9 of Figure 2 or the metalplate ID, of Figure 3, instead of in the glass stem press I. Byproviding for the stem reinforcing member to take the major brunt of theshock, instead of having the full impact transmitted to the glass stempress, chipping of the glass and the consequent defacement of thecoating of fluorescent material is reduced substantially.

What I claim is: p I A lamp mount comprising a glass flare; a stem pressformed integral therewith; at least one lead wire sealed in said pressand extending therethrough; two electrode-supporting wires, at least aportion of which are sealed in said press; an elongated tubularelectrode mounted on said lead wire and said. electrode-supportingwires; and a rigid stress-absorbing means comprising 3 t awire memberwound around and fixedly conmm nected to the lead wire and theelectrode-sup- STATES PATENTS porting wires intermediate the base of theelec- Number Name D te trade and the top of the stem press. 1,600,595 eept 19 6 1,824,452 Warnser Sept. 22, 1931 HE BE T H, CHUN, 2,23 ,476Fletcher Mar. 4, 1941 2,254,857 Renter Sept. 2, 1941 REFERENCES CITEDfillier f'fb. lg, 1942 181 ay1,194 The following references are ofrecord in the 2,395,145 Ranney Feb 19, 1946 file of this patent: 10

